The present invention relates to a bead releasing head provided with a bead removing tool for assembling/disassembling a tire, to be used on a tire-fitting machine, i.e. a tire assembling/disassembling machine.
As known, tire-fitting machines have a series of tools designed to carry out and assist in operations of tire fitting on, and disassembling from, wheel-rims.
For carrying out disassembling operations use is made of a bead releasing disk or roller designed to act on the tire-beads and of a removing lever or tool which is inserted between the tire bead and the edge of the wheel-rim, once the bead releasing operation has been completed both on the front side and on the back side of the tire, to cause the removal from the wheel-rim first of one side of the tire, and then of the other.
It has already been suggested to fit a bead releasing disk or roller D and a removing tool U on one head T mounted for rotation and lockable in position by means of a support arm or upright M, as shown in FIGS. 1 to 4 of the accompanying drawings which show a bifunctional tool-carrying head T of a known type, in the various bead releasing and removing stages both at the front and back side of a wheel-rim C for disassembling a tire P from its respective wheel-rim C.
The bead releasing disk D and tool U are arranged facing each other, whereby following a 180xc2x0 rotation of the head T on its respective support arm or upright M, the disk D or the bead removing tool U can be brought to its working position, i.e. it can be oriented facing the tire P to be disassembled from its respective wheel-rim C.
In any case, the tool carrying heads T require that the operator carries out quite laborious positioning and setting manoeuvres that heavily slow down the working steps and entail a certain dexterity that is acquired only with adequate experience. After each operation, each tool D, U, at the operator""s discretion, should be moved again to the rest position; in the real practice, however, such an operation is often ignored, and thus in the subsequent bead releasing operation it will be necessary for the operator to displace the tools to their correct position before being able to use them.
Moreover, after intervention of the bead releasing disk D that has thus urged the bead Pa of tire P inside an intermediate groove Ca in wheel-rim C through its active edge or front, within the same time interval in which one tool D, U is replaced by the other, i.e. to remove the bead releasing disk D and bring the removing tool U to its working position, bead Pa of removed tire P tends resiliently to return to its pre-release position, i.e. towards the outer edge Ce of the wheel-rim, thus at least partly obstructing the passage delimited by edge Ca and bead Pa under the action of the bead releasing disk D, thereby making the insertion of bead removing tool U much more difficult.
The main object of the present invention is to eliminate the above shortcomings of the state of the art by contriving a bead releasing head for tire assembling/disassembling machines that makes it possible to eliminate the need to put the head in position again after the operation of a tool, to have the possibility to use the other tool to release the beads and remove the tires from the their respective wheel-rims, thus making the bead releasing and removing operations simpler, swifter and more expeditious.
This and other objects that will be better apparent below are attained by a bead releasing and removing head according to the present invention for a tire assembling/disassembling machine, including an upright structure anchored to the said tire assembling/disassembling machine, a bead releasing disk and a bead removing tool having a work tip, both supported at the top of said upright structure, wherein the said bead removing tool is slidably supported by the said head on the same side and in the same direction as the said bead releasing disk and comprises driving means arranged to cause said bead removing tool to be displaced, upon control, between an outwardly extended working position and a withdrawn rest position, while sliding over and flash with said bead releasing disk along a curved path, thereby overtaking the said bead releasing disk to reach said extending working position.